The Astronomical League of the Philippines’ (ALP) Philippine Messier Marathon Open is an annual star party conducted under the dark clear skies of Caliraya, Laguna, where astronomy-enthusiasts in the country gather to observe and meet fellow enthusiasts. The highlight of the event is the messier marathon — astro-enthusiasts attempt to observe and identify all the 110 m-objects in just one night. More information may be found in ALP’s official report.

Astro-enthusiats from various astronomical organizations in the Philippines attend this annual astro-gathering in a dark-sky site in Caliraya, Laguna (Photo Credit: James Kevin Ty)

This event hosted by the Astronomical League of the Philippines is by far the largest star party and astro-gathering in the Philippines.